1. Field of the Invention
The present invention relates to enzyme preparations for bound and formed foods, and methods for producing a bound and formed food. The present invention also relates to bound and formed foods produced by such a method.
2. Discussion of the Background
There are many reports concerning techniques on binding food raw materials using transglutaminase. Japanese Patent No. 1927253 discloses a technique to produce a bound and formed food with the use of only transglutaminase. The technique described in this patent is groundbreaking in the sense that it developed a novel use of transglutaminase. However, because of insufficient binding strength, techniques using a variety of other components with transglutaminase have been studied, and put into practical application.
Japanese Patent Nos. 3353383 and 3353503 disclose bound and formed foods, in which transglutaminase and its substrate caseins are used in combination. The methods described in these patents are applicable to a wide range of food raw materials, including not only livestock meat, but fishery products such as fish meat, squid, and crab, and fish roe such as salmon roe, herring roe, salted salmon roe, and salted cod roe. The methods described in these patents are inventions concerning highly versatile binding and forming methods that enable a food to be bound in the raw state without influencing taste and flavor.
Because of recent problems of food allergies, the use of milk-derived proteins for processed foods is not always possible. In this connection, binding methods that use transglutaminase and non-casein proteins have been studied. Japanese Patent No. 3407599 discloses a binding and forming method that uses collagen and transglutaminase as the active ingredients without using casein. However, because collagen has the property to develop a high viscosity when dissolved in water, the method requires the collagen to be dissolved in cold water of 10° C. or less, and the bonding procedure must immediately follow the dissolving of the collagen. The method is therefore problematic in terms of handling. It should also be noted that the binding strength is weak in the absence of a salt, and practical effects cannot be expected in this case.
In this connection, International Publication WO 02/080700 discloses an enzyme preparation for binding food raw materials, and a method of production of bound and formed food using the enzyme preparation. The invention described in this publication uses a specific collagen in which the total number of hydroxyproline and proline residues (hereinafter, also referred to as “imino acids”) is less than 20% of the total amino acid residues in the collagen, and the specific collagen and transglutaminase are contained as the active ingredients. JP-A-2006-246716 describes suppressing the gelling of collagen at low temperatures by preferably blending salts, for example, potassium chloride, and calcium chloride, to form an adhesive containing transglutaminase, collagen, and salts for a bound and formed food. However, because the invention described in JP-A-2006-246716 uses calcium chloride to suppress the gelling of collagen at low temperatures, the invention of this publication is completely different in the way calcium chloride is used in the present invention, as will be described later. Accordingly, the invention described in JP-A-2006-246716 does not suggest the present invention.
Further, the type of collagen that can be used as the specific collagen is essentially fish skin-derived collagen. As such, there are cases where preparations that contain fish collagen are not usable for livestock meat processed products that use pork, beef, and chicken, because fish collagen has a different protein origin from these products. Particularly in the European market where processed foods that use raw materials originating in fish must be labeled with a listing of allergenic ingredients, the use of fish collagen for livestock meat processed products is often more restricted than in other regions.
The binding techniques currently available all use specific protein materials in a blend, and no technique is available that can satisfy the need to be free of different proteins. Despite the need for a binding technique that does not use protein materials, no technique has been developed that can provide practical levels of binding strength without using protein materials.